Design And Principle Of Operation - Samson 2333 Mounting And Operating Instructions

Design and principle of operation

3 Design and principle of oper-
ation
See Fig. 1 and Fig. 2.
The medium flows through the globe valve
(1) in the direction indicated by the arrow.
The position of the plug determines the flow
rate across the area released between plug
(3) and seat (2). The travel position of the pi-
lot valve (5) determines the pressure condi-
tions across the valve.
The forces created by the upstream pressure
p acting on the plug surface and by the
1
control pressure p
S
bellows (4) or balancing diaphragm (11)
and the force of set point spring (3.1) are
compared.
In the Type 2333 Pressure Reducing Valve, a
rise in downstream pressure p
pilot valve to close. The control pressure p
increases and the plug of the main valve
starts to close. When the pilot valve is closed
(p = p ), the pressure reducing valve (main
S 1
valve) is also completely closed.
Table 1: Minimum differential pressure ∆p
Valve size
Valve balanced by
a bellows for steam
applications
Valve balanced by
a bellows for air/
water
Valve balanced by
a diaphragm
6
acting on the balancing
causes the
2
DN 65 DN 80 DN 100 DN 125 DN 150 DN 200 DN 250 DN 300 DN 400
0.2 bar (640 cm² actuator)
0.4 bar (320 cm² actuator)
–
Together with the pilot valve, the fixed re-
striction (8) or the Venturi nozzle (6) create
the control pressure p
If the downstream pressure p
low the set point, the pilot valve opens. The
control pressure p
resulting from the upstream pressure p
ing on the plug surface causes the valve to
open.
To ensure proper functioning, the minimum
differential pressure ∆p
must be available as specified depending on
the field of application.
The regulator version for steam is only avail-
able with valves balanced by a bellows. This
version has a compensation chamber (10)
already fitted in the control line. The needle
valve (9) is open and lead-sealed. A com-
pensation chamber and needle valve are ad-
ditionally required for the version for steam
S
in valve sizes DN 65 to 100.
Before start-up, fill the compensation cham-
ber with water at the top filler opening.
min
1.9 bar 2.0 bar 1.4 bar 1.4 bar
1.0 bar 1.0 bar 0.7 bar 0.7 bar
0.8 bar 0.8 bar 0.4 bar 0.4 bar 0.5 bar 0.3 bar
.
S
falls again be-
2
falls as a result. The force
S
listed in Table 1
min
–
–
EB 2552-1 EN
act-
1
–
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